Mirror-carrying flash lamp

ABSTRACT

In a flash lamp in which an emission of an arc is generated by cooperation of a cathode ( 8 ), an anode ( 9 ), trigger probe electrodes ( 12, 13 ), and a sparker electrode ( 16 ) which are contained in an envelope (H) having a light projection window ( 4 ), and this emission is emitted from the light projection window ( 4 ), a mirror structure ( 20, 30, 40 ) is fixed at an inner end portion of an exhaust pipe ( 21, 34, 44 ) secured to the center of a stem ( 6 ) disposed at a bottom portion of the envelope (H). The mirror structure ( 20, 30, 40 ) comprises a mirror surface ( 24, 32, 42 ), contained in the envelope (H), facing the light projection window ( 4 ), and an exhaust path ( 26, 33, 43 ), formed at a position inside the mirror structure ( 20, 30, 40 ) separated from the mirror surface ( 24, 32, 42 ), communicating an exhaust port ( 21   c   , 34   b   , 44   b ) of the exhaust pipe ( 21, 34, 44 ) and the exterior of the mirror structure ( 20, 30, 40 ) to each other.

TECHNICAL FIELD

The present invention relates to a flash lamp equipped with a mirror,utilized as a light source for spectroscopy, emission analysis or thelike, a stroboscopic light source, a light source for processinghigh-quality images, or the like.

BACKGROUND ART

A conventional technique in such a field is disclosed in Japanese PatentPublication No. HEI 7-120518. In the mirror-equipped flash lampdescribed in the above-mentioned publication, a cathode and an anode aredisposed facing each other inside a bulb made of glass, the front end ofa trigger probe electrode is located between the cathode and the anode,and an inert gas, such as xenon or argon, is encapsulated in the bulb.Further, for attaining high-output light, an ellipsoidal mirror isdisposed inside the bulb, and the cathode is inserted in an openingformed in the bottom part of the ellipsoidal mirror, whereby an arcemission point is formed at a first focal point inside the ellipsoidalmirror. By the provision of such an ellipsoidal mirror inside the bulb,a high-output flash lamp is produced.

DISCLOSURE OF THE INVENTION

Due to the above-mentioned configuration, however, the following problemexists in the conventional mirror-equipped flash lamp.

Namely, since the bottom part of the ellipsoidal mirror is formed withan opening, light reflected by the ellipsoidal mirror forms a darkportion in its irradiation area under the influence of the opening, thuslacking uniformity. As a result, when irradiation light is to beintroduced into a small-diameter fiber or slit, there have been caseswhere shortages or inconsistencies in quantity of light occur. WhileJapanese Patent Publication No. SHO 56-50384 also discloses a xenon lampequipped with a mirror, the mirror in this case is also formed with anopening for receiving a pedestal for supporting an electrode.

For solving the above-mentioned problem, it is an object of the presentinvention, in particular, to provide a mirror-equipped flash lampadapted to generate uniform light whose irradiation inconsistencies arevery small.

The mirror-equipped flash lamp in accordance with the present inventionis a flash lamp in which an arc emission is generated by cooperation ofa cathode, an anode, a trigger probe electrode, and a sparker electrodewhich are contained in an envelope having a light projection window, andthis emission is emitted from the light projection window; wherein amirror structure is fixed at an inner end portion of an exhaust pipesecured to a center of a stem disposed at a bottom portion of theenvelope; the mirror structure comprising a mirror surface, contained inthe envelope, facing the light projection window, and an exhaust path,formed at a position inside the mirror structure separated from themirror surface, communicating an exhaust port of the exhaust pipe andthe exterior of the mirror structure to each other.

In this mirror-equipped flash lamp, when a predetermined voltage isapplied between the cathode and the anode, and a trigger voltage isapplied to the trigger probe electrode and the sparker electrode, adischarge occurs at the trigger probe electrode and, along with thisdischarge, a main discharge of an arc occurs between the cathode and theanode. The resulting emission is reflected by the mirror surface, so asto be emitted from the light projection window. Such a mirror surface isformed in the mirror structure, which is fixed at the inner end portionof the exhaust pipe. However, since the exhaust pipe is utilized forletting out the air from within the envelope and introducing an inertgas into the envelope, it is not allowed to close the exhaust port ofthe exhaust pipe facing the interior of the envelope. Therefore, theexhaust path for communicating the exhaust port of the exhaust pipe andthe exterior of the mirror structure to each other is formed inside themirror structure, and is disposed at a position separated from themirror surface, i.e., at a position not cutting out the mirror surface.As a result, the mirror surface can be made as a complete surfacewithout opening a hole therein. Also, post-processing such as boring ahole in the mirror surface is not necessary, the whole mirror surfacecan be used effectively as a reflecting surface, and the reflectioncharacteristics inherent in the mirror surface can fully be utilized.

Preferably, in this case, the mirror structure comprises a cup-shapedmirror holder having a bottom part fixed at the inner end portion of theexhaust pipe; a mirror body, mounted in an opening of the mirror holder,having the mirror surface at a top face thereof; a mirror body supportsurface, extending toward inside the mirror holder at a part of an innerwall face of the mirror holder, for supporting the mirror body; and theexhaust path formed between a bottom face of the mirror body and abottom face of the mirror holder. When such a configuration is employed,the mirror structure comprises a mirror holder and a mirror body whichare separated from each other and thus can be made of differentmaterials, whereby the manufacturing cost can be cut down. Also, asimple assembling operation of exchanging mirror bodies with respect tothe mirror holder can provide the mirror structure with a desirablemirror surface (e.g., rounded mirror, parabolic mirror, ellipsoidalmirror, polyhedron mirror, or the like). Further, making the mirrorholder and the mirror body separate from each other is advantageous inthat, since the mirror body is supported by the mirror body supportsurface such that the bottom faces of the mirror holder and mirror bodydo not come into contact with each other when the mirror body is mountedto the mirror holder, a space can positively be formed between thebottom faces of the mirror holder and mirror body, and this space caneffectively be used as the exhaust path, whereby the exhaust path caneasily be formed at a position separated from the mirror surface, i.e.,at a position not cutting out the mirror surface. Also, as the exhaustpath is disposed at this position, the exhaust port of the exhaust pipeand the exterior of the mirror structure can easily be communicated toeach other. For example, a simple drilling process for only providing aside wall or bottom wall of the mirror holder with a hole communicatingwith the exhaust path can produce a gas port in the mirror structure.

Also, it is preferred that a mirror body fixing ring abutting against aperipheral edge in the top face of the mirror body and abutting againstthe inner wall face of the mirror holder be further provided. When sucha configuration is employed, at the time of assembling the mirrorstructure, the mirror body can be constrained by the mirror body fixingring as the latter is introduced into the mirror holder after the mirrorbody is mounted into the opening of the cup-shaped mirror holder,whereby the mirror body can be secured simply and reliably in the mirrorholder.

Further, it is preferred that the mirror holder reduce its diameter onthe bottom face side thereof at a part of the side wall thereof, so asto provide an inner wall face of the mirror holder with the mirror bodysupport surface. When such a configuration is employed, at the time ofassembling the mirror structure, even if the mirror body is simplymounted into the opening of the mirror holder, the bottom faces of themirror holder and mirror body can be kept from coming into contact witheach other, whereby the exhaust path can be secured easily.

Further, it is preferred that the mirror body be made of glass. Whensuch a configuration is employed, in the forming of the mirror surface,the surface processing is easier than that in metals such as aluminum,thereby yielding a surface which not only can be made at a lowermanufacturing cost but also has a low surface roughness and high surfaceprecision. Also, when aluminum is vapor-deposited on a glass surface toform a mirror surface, a firm specular surface would be formed on theglass surface, whereby a highly durable mirror surface can be obtained.

Further, it is preferred that a gas port of the exhaust path is formedin a flat bottom wall of the mirror holder so as to penetratetherethrough. When such a configuration is employed, a drilling processfor forming the gas port in the mirror holder becomes easy.

Further, the mirror surface preferably constitutes a rounded mirror.When such a configuration is employed, it is not necessary to form anopening at the bottom part thereof as in the case of an ellipsoidalmirror, whereby light-collecting efficiency can be improved.

Further, it is preferred that an arc emission part be disposed at afocal position of the mirror surface. Employing such a configuration ina rounded mirror enables the mirror surface to reliably collect light.

Also, it is preferred that the mirror structure comprise a block body,secured at the inner end portion of the exhaust pipe, having the mirrorsurface integrally formed at a top face thereof and the exhaust paththerewithin. When such a configuration is employed, no additional stepof assembling the mirror structure is needed, whereby the workingefficiency of assembling the flash lamp would improve.

Further, it is preferred that, at a center of the block body in thebottom face thereof, a pipe insertion hole, extending in a center axisdirection of the block body, for receiving the inner end portion of theexhaust pipe be provided, and that the exhaust pipe be secured to theblock body with a screw. When such a configuration is employed, theassembling of the block body and the exhaust pipe to each other can becarried out easily and reliably.

Further, it is preferred that a gas port of the exhaust path be formedat a peripheral side face of the block body. When such a configurationis employed, a simple drilling process can communicate the pipeinsertion hole and the exhaust path to each other at the time of formingthe block body with the gas port.

Further, the mirror surface preferably constitutes a rounded mirror.When such a configuration is employed, it is not necessary to form anopening at the bottom part thereof as in the case of an ellipsoidalmirror, whereby light-collecting efficiency can be improved.

Further, it is preferred that an arc emission part be disposed at afocal position of the mirror surface. Employing such a configuration ina rounded mirror enables the mirror surface to reliably collect light.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a mirror-equipped flash lamp in accordance withthe present invention;

FIG. 2 is a sectional view taken along the line II—II of FIG. 1;

FIG. 3 is a plan view of a mirror structure employed in the flash lampshown in FIG. 1;

FIG. 4 is a sectional view taken along the line IV—IV of FIG. 3;

FIG. 5 is an exploded perspective view of the mirror structure;

FIG. 6 is a plan view showing a modified example of the mirrorstructure;

FIG. 7 is a sectional view taken along the line VII—VII of FIG. 6;

FIG. 8 is a sectional view taken along the line VIII—VIII of FIG. 6;

FIG. 9 is a plan view showing another modified example of the mirrorstructure; and

FIG. 10 is a sectional view taken along the line X—X of FIG. 9.

BEST MODE FOR CARRYING OUT THE INVENTION

In the following, preferred embodiments of the mirror-equipped flashlamp in accordance with the present invention will be explained indetail with reference to the drawings.

FIG. 1 is a plan view showing the appearance of a mirror-equipped flashlamp in accordance with the present invention, whereas FIG. 2 is asectional view taken along the line II—II of FIG. 1. The mirror-equippedflash lamp 1 shown in these drawings has a cylindrical side tube 2 madeof covar metal, a circular first opening 3 is formed at one end of theside tube 2, and a light projection window 4 made of sapphire glass issecured to the side tube 2 so as to close the first opening 3. Further,a circular second opening 5 is formed at the other end of the side tube2, and a disk-shaped stem 6 made of covar glass is secured to the sidetube 2 so as to close the second opening 5. Also, a cylindrical stemholder 7 made of covar metal is fused to the peripheral side face of thestem 6, so that the flange portion 7 a of the stem holder 7 and theflange 2 a of the side tube 2 can be arc-welded to each other, therebymaking it easier for the stem 6 and the side tube 2 to be secured toeach other. Thus, a hermetic type envelope H of the flash lamp 1 isconstructed.

Further, a cathode 8 and an anode 9 which are adapted to cause an arcdischarge are disposed inside the envelope H, whereas these electrodes8, 9 are secured to the stem 6 with the aid of stem pins 10, 11. Also,inside the envelope H, two trigger probe electrodes 12, 13 are disposedsuch that their front ends are located between the cathode 8 and theanode 9, whereas these electrodes 12, 13 are secured to the stem 6 withthe aid of stem pins 14, 15. Further, a sparker electrode 16 is disposedinside the envelope H, and is secured to the stem 6 with the aid of astem pin 17. The inside of the envelope H is kept at a high pressure,with xenon gas as an example of the inert gas being encapsulatedtherein.

When a predetermined voltage is applied between the cathode 8 and theanode 9 by way of the stem pins 10, 11, and a trigger voltage is appliedto the trigger probe electrodes 12, 13 and the sparker electrode 16 byway of the stem pins 14, 15, 17, a discharge occurs at the trigger probeelectrodes 12, 13 and, along with this discharge, a main discharge of anarc occurs between the cathode 8 and the anode 9. The emission at thistime is reflected by a mirror structure 20 which will be explainedlater, so as to be emitted from the light projection window 4.

This mirror structure 20 is disposed among the cathode 8, the anode 9,and the stem 6, so as to be positioned directly below an arc emissionpart S formed between the cathode 8 and the anode 9. For enabling suchan arrangement, the mirror structure 20 is fixed at an inner end portion21 a of an exhaust pipe 21, made of covar metal, secured to thedisk-shaped stem 6. Here, this exhaust pipe 21 extends in the tube axisdirection so as to penetrate through the center of the stem 6.

As shown in FIGS. 3 to 5, the mirror structure 20 is constructed as adividable type and has a cup-shaped mirror holder 22 made of stainless,whereas this mirror holder 22 is formed like a cylinder having a bottomwall 22 a with a pipe insertion hole 22 b, formed at the center thereof,for receiving the exhaust pipe 21. A flange portion 21 b is formed at anend part of the exhaust pipe 21, whereby the inner end portion 21 a ofthe exhaust pipe 21 and the bottom wall 22 a of the mirror holder 22 canbe arc-welded to each other when the flange portion 21 b is caused toabut against the bottom wall 22 a of the mirror holder 22. Thus,securing the exhaust pipe 21 to the center of the mirror holder 22enables a centering structure for a mirror surface 24 which will bementioned later.

Further, a disk-shaped mirror body 23 is closely fitted in the mirrorholder 22 so as to be concentric therewith. This mirror body 23 is madeof a glass material and has such a diameter that it can be inserted intothe mirror holder 22 from the opening 22 c thereof. Also, the top faceof the mirror body 23 is formed with the mirror surface 24, facing thelight projection window 4, shaped into a rounded mirror whileconstituting a concave mirror. Here, the rounded mirror refers to amirror made of a curved surface with a constant radius of curvaturehaving a single focal point. This mirror surface 24 is formed byvapor-depositing aluminum onto a glass surface. When glass is thusemployed in the mirror body 23, in the forming of the mirror surface 24,the surface processing is easier than that in metals such as aluminum,thereby yielding the mirror surface 24 which not only can be made at alower manufacturing cost but also has a low surface roughness and highsurface precision. Also, when aluminum is vapor-deposited on the glassto form the mirror surface 24, a firm specular surface would be formedon the glass, whereby the highly durable mirror surface 24 can beobtained. Here, the mirror body 23 may also be made of metals such asaluminum, copper, and the like.

Also, a part of the side wall 22 d of the mirror holder 22 is caused toreduce its diameter on the bottom wall 22 a side by drawing, thusyielding a reduced diameter portion 22 e, whereby an annular mirror bodysupport surface 25 extending inward is formed in the inner wall face ofthe mirror holder 22. Hence, when the bottom face 23 b of the mirrorbody 23 abuts against the mirror body support surface 25, the bottomface 22f of the mirror holder 22 and the bottom face 23 b of the mirrorbody 23 are kept from coming into contact with each other, and theexhaust port 21 c of exhaust pipe 21 is prevented from being closed bythe mirror body 23.

Thus, a columnar space can be formed between the bottom face 22 f of themirror holder 22 and the bottom face 23 b of the mirror body 23. As thisspace is effectively utilized as an exhaust path 26, the latter iseasily formed at a position separated from the mirror surface 24, i.e.,at a position not cutting out the mirror surface 24. As a result, themirror surface 24 can be made as a complete surface without opening ahole therein. Therefore, post-processing such as boring a hole in themirror surface 24 is not necessary, the whole mirror surface 24 can beused effectively as a reflecting surface, and the reflectioncharacteristics inherent in the mirror surface 24 can fully be utilized.

Further, three gas ports 27 of the exhaust path 26 are formed in thebottom wall 22 a of the mirror holder 22 so as to surround the exhaustpipe 21, each gas port 27 being formed in the flat bottom wall 22 a bydrilling. Thus, the exhaust path 26 communicates the exhaust port 21 cof the exhaust pipe 21 and the exterior of the mirror structure 20 toeach other. As a consequence, by use of the exhaust pipe 21, after theair inside the envelope H is let out under vacuum, the inside of theenvelope H can be filled with an inert gas such as xenon gas. Afterxenon gas is encapsulated, an outer end portion of the exhaust pipe 21is sealed.

Here, as means for securing the mirror body 23 inside the mirror holder22, a C-shaped mirror body fixing ring 28 is utilized. This mirror bodyfixing ring 28 is made of a stainless material, and has such a diameterthat it can be mounted in the opening 22 c of the mirror holder 22.Hence, when the mirror body 23 is mounted into the mirror holder 22 fromthe opening 22 c thereof, as the mirror body fixing ring 28 isintroduced into the mirror holder 22, the mirror body fixing ring 28abuts against the peripheral edge 23 a in the top face of the mirrorbody 23 and the inner wall face of the mirror holder 22. Then, as themirror body fixing ring 28 and the mirror holder 22 are spot-welded toeach other, the mirror body 23 is firmly secured in the mirror holder 22by cooperation of the mirror body fixing ring 28 and the mirror bodysupport surface 25. Here, the mirror body 23 can also be secured if anunshown pawl is formed at a top portion of the mirror holder 22 and bentinward. Also, if the mirror body fixing ring 28 is provided with aspring force, there will be cases where it is not necessary for themirror body fixing ring 28 and the mirror holder 22 to be weldedtogether.

Since the rounded mirror is employed as the mirror surface 24, thusconfigured mirror structure 20 can cause the arc emission part S (seeFIG. 2) located between the cathode 8 and the anode 9 to align with thefocal position (center of curvature) of the mirror surface 24, thusallowing the mirror surface 24 to reliably collect light.

A modified example of the mirror structure will now be explained.

As shown in FIGS. 6 to 8, another mirror structure 30 is constituted bya columnar block body 31 made of aluminum, a mirror surface 32constituting a rounded mirror is formed at the top face of the blockbody 31, and the mirror surface 32 is finished as a specular surface byvapor deposition of aluminum. Inside the block body 31, an exhaust path33 is formed at a position separated from the mirror surface 32, i.e.,at a position not cutting out the mirror surface 32. This exhaust path33 comprises therewithin a first exhaust path 33 a diametricallyextending like a line so as to penetrate through the peripheral sideface 31 a of the block body 31, and a second exhaust path 33 b extendingin the center axis direction so as to penetrate through the bottom face31 b of the block body 31, which are formed by drilling. Namely, theexhaust path 33 is formed like letter T within the block body 31.

Also, the first exhaust path 33 a has a pair of gas ports 35 formed onthe right and left side of the peripheral side face 31 a, whereas thesecond exhaust path 33 b is utilized as a pipe insertion hole. This pipeinsertion hole 33 b has such a diameter that an exhaust pipe 34 can betightly fitted therein, and aligns with the center axis of the blockbody 31 at its center in the bottom face 31 b thereof, thus enabling acentering structure for the mirror surface 32. Further, a screw hole 37is formed so as to extend from the peripheral side face 31 a to the pipeinsertion hole 33 b.

Hence, a rod-shaped spacer 38 slightly thinner than the first exhaustpath 33 a is inserted into the latter so as not to close an exhaust port34 b of the exhaust pipe 34. Thereafter, the exhaust pipe 34 is insertedinto the pipe insertion hole 33 b of the block body 31, and a screw 36is threaded into the screw hole 37. As a result, the block body 31 isreliably secured to the inner end portion 34 a of the exhaust pipe 34,and the exhaust port 34 b of the exhaust pipe 34 and the exterior arecommunicated to each other by way of the exhaust path 33. Here, theexhaust pipe 34 may be secured to the block body 31 by welding or thelike after being inserted into the pipe insertion hole 33 b. Also, sincethe rounded mirror is employed as the mirror surface 32, the arcemission part S (see FIG. 2) located between the cathode 8 and the anode9 aligns with the focal position (center of curvature) of the mirrorsurface 32, thus allowing the mirror surface 32 to reliably collectlight.

Another modified example of the mirror structure will now be explained.

As shown in FIGS. 9 and 10, still another mirror structure 40 isconstituted by a columnar block body 41 made of aluminum, a mirrorsurface 42 constituting a rounded mirror is formed at the top face ofthe block body 41, and the mirror surface 42 is finished as a specularsurface by vapor deposition of aluminum. Inside the block body 41, anexhaust path 43 is formed at a position separated from the mirrorsurface 42, i.e., at a position not cutting out the mirror surface 42.This exhaust path 43 comprises therewithin a first exhaust path 43 aradially extending like a line from the peripheral side face 41 a of theblock body 41 so as to be cut into the center of the block body 41, anda second exhaust path 43 b extending in the center axis direction so asto penetrate through the bottom face 41 b of the block body 41, whichare formed by drilling. Namely, the exhaust path 43 is formed likeletter L within the block body 41.

Also, the first exhaust path 43 a has one gas port 45 at the peripheralside face 41 a thereof, whereas the second exhaust path 43 b is utilizedas a pipe insertion hole. This pipe insertion hole 43 b has such adiameter that an exhaust pipe 44 can be tightly fitted therein, andaligns with the center axis of the block body 41 at its center in thebottom face 41 b thereof, thus enabling a centering structure for themirror surface 42. Further, a screw hole 47 is formed so as to extendfrom the peripheral side face 41 a to the pipe insertion hole 43 b.

After the exhaust pipe 44 is inserted into the pipe insertion hole 43 bof the block body 41, a screw 46 is threaded into the screw hole 47,whereby the block body 41 is reliably secured to the inner end portion44 a of the exhaust pipe 44, and the exhaust port 44 b of the exhaustpipe 44 and the exterior are communicated to each other by way of theexhaust path 43. Here, the exhaust pipe 44 may be secured to the blockbody 41 by welding or the like after being inserted into the pipeinsertion hole 43 b.

The present invention is not limited to the above-mentioned variousembodiments. For example, the mirror surfaces 24, 32, 42 are notrestricted to rounded mirrors, but may be parabolic mirrors, ellipsoidalmirrors, or polyhedron mirrors.

As a consequence of the foregoing configuration, the mirror-equippedflash lamp in accordance with the present invention can yield thefollowing effects. Namely, since a mirror structure is fixed at an innerend portion of an exhaust pipe, while the mirror structure comprises amirror surface, contained in an envelope, facing a light projectionwindow, and an exhaust path formed at a position inside the mirrorstructure separated from the mirror surface, a structure in which themirror surface is free of holes can be attained, and uniform light canbe generated with very small irradiation inconsistencies.

INDUSTRIAL APPLICABILITY

The mirror-equipped flash lamp in accordance with the present inventioncan be utilized as a light source for spectroscopy, emission analysis orthe like, a stroboscopic light source, a light source for processinghigh-quality images, or the like.

What is claimed is:
 1. A flash lamp in which an arc emission between ananode and a cathode is reflected by a mirror surface and is emitted froma window of an envelope, said flash lamp comprising: an exhaust pipepenetrating through a stem of said envelope so as to project inside saidenvelope, and a mirror structure, supported by said exhaust pipe, havingsaid mirror surface positioned between an inner end portion of saidexhaust pipe and said window, and an exhaust path, separated from saidmirror surface, for communicating from said exhaust pipe to the insideof said envelope.
 2. A flash lamp according to claim 1, wherein saidmirror structure comprises: a cup-shaped mirror holder having a bottompart fixed at said inner end portion of said exhaust pipe; a mirrorbody, mounted in an opening of said mirror holder, having said mirrorsurface at a top face thereof; a mirror body support surface, extendingtoward inside said mirror holder at a part of an inner wall face of saidmirror holder, for supporting said mirror body; and said exhaust pathformed between a bottom face of said mirror body and a bottom face ofsaid mirror holder.
 3. A flash lamp according to claim 2, furthercomprising a mirror body fixing ring abutting against a peripheral edgein the top face of said mirror body and abutting against said inner wallface of said mirror holder.
 4. A flash lamp according to claim 2,wherein said mirror holder reduces a diameter on the bottom face sidethereof at a part of a side wall thereof, so as to provide an inner wallface of said mirror holder with said mirror body support surface.
 5. Aflash lamp according to claim 2, wherein said mirror body is made ofglass.
 6. A flash lamp according to claim 2, wherein a gas port of saidexhaust path is formed in a flat bottom wall of said mirror holder so asto penetrate therethrough.
 7. A flash lamp according to claim 1, whereinsaid mirror structure comprises: a block body, secured at said inner endportion of said exhaust pipe, having said mirror surface integrallyformed at a top face thereof and said exhaust path therewithin.
 8. Aflash lamp according to claim 7, wherein a pipe insertion hole,extending in a center axis direction of said block body, for receivingsaid inner end portion of said exhaust pipe is provided at a center ofsaid block body in a bottom face thereof, said exhaust pipe beingsecured to said block body with a screw.
 9. A flash lamp according toclaim 8, wherein a gas port of said exhaust path is formed at aperipheral side face of said block body.
 10. A flash lamp comprising: ananode and a cathode causing an arc emission therebetween; an envelopeaccommodating said anode and cathode; an exhaust pipe penetratingthrough a stem of said envelope; and a mirror structure supported bysaid exhaust pipe, said mirror structure being arranged in and separatedfrom an inner surface of said envelope, said mirror structure having amirror surface at its end.
 11. The flash lamp according to claim 10,said mirror structure having a cavity between said mirror surface andthe end of said exhaust pipe inside the envelope.
 12. The flash lampaccording to claim 11, wherein said mirror structure has an openingcommunicating from said cavity to outside said mirror structure.